1. Field
It is related to a defect pixel correction circuit for correcting a defect of an image sensor such as CCD/CMOS sensor digitally, a system using the same, and a defect pixel correcting method.
2. Description of Related Art
In general, it is known that the defect pixel occurs due to a partial crystal defect etc. of a semiconductor substrate in image sensors such as CCD (Charge Coupled Device) and CMOS sensors.
When the defect pixel of such an image sensor is determined and corrected, it is determined whether a noteworthy pixel is defected from a peripheral referring pixel by using the sub matrix of n×n (where n≧2, generally about n=3). When the noteworthy pixel is a defect pixel, the noteworthy pixel is replaced by the correcting pixel generated by using the peripheral referring pixel.
The technique concerning defect pixel correction of such an image sensor is disclosed in Japanese Unexamined Patent Publication No. 2000-101924, Japanese Unexamined Patent Publication No. 2004-235980 and Japanese Unexamined Patent Publication No. 2002-223391.
However, there is the defect that ranges to one direction (for example, vertical direction) in the image sensor in recent years, and a lot of defect pixels will be included in the referring pixel in the technique concerning the defect pixel correction that uses the sub matrix of n×n of the conventional technology. Therefore, the determination of the defect of the image sensor with the defect that ranges to such one direction and the appropriate replacement with the correcting pixel are difficult and problems in the conventional technology.